open off.bios with Phoenixtool 2.73 (or 2.66), press Structure button, and insert two modules - a combined pubkey+marker module (GUID CDFFEBFB-17DC-46BC-9B75-59B861920913) and a signing key (GUID 15634458-E8A4-436D-AC2F-57E33E534CCF) into the Volume with Dummy MSOA module